Which type of competition will help me learn more?
In October there are going to be 2 tournaments that I'm interested competing in, the SAMBO Open, and the East Coast Judo Championships. I've been doing Judo for about 4 months, so I'm a beginner by every stretch of the imagination.
Generally speaking will I get the most out of the SAMBO competition which is open, where I will most likely be paired against someone with a lot more experience than me, or the EC Judo Championships where, there are different levels?
My guess is that you might be a bit more overwhelmed at the SAMBO open, as you are not as familiar with it's ruleset and greater emphasis on groundwork, along with the fact that you could be going against more experienced people. I'd go for the Judo comp against people with a similar experience level for your first event. Once you get comfortable enough in your training to understand what you're good at and what you aren't, then decide if you'd like to compete under a less restrictive ruleset, which SAMBO definitely has.
I second the above post. While I find I get a lot out of rolling with people massively more experienced than I am in class, I find it considerably less educational to go up against people who are much better than me in competition, not the least of these reasons being because when they are going full out the fights tend to last all of about 5 seconds. Obviously though, this depends on the magnitude of the skill difference.